1. Technical Field
The present disclosure relates to a coupler for securing adjacent rods together in fixed relation. More specifically, the present disclosure relates to a rod-to-rod coupler for securing adjacent spinal rods together in fixed relation during spinal correction procedures.
2. Background of Related Art
Spinal rod systems for correcting and stabilizing spinal curvatures and for facilitating spinal fusion in surgical procedures to correct spinal disorders or degenerative conditions are well known in the art. Typically, these spinal rod systems include a plurality of bone fixation members and a pair of elongated spinal rods. The bone fixation members each have a first end which is secured to a vertebrae and a second end adapted to be fixedly connected to a spinal rod. During a spinal correction procedure, a plurality of fixation members are fixed to vertebrae at various points along the vertical length of the spine on each side of the spinal midline. Thereafter, each of the fixation members on each side of the spinal midline is linked with the other fixation members by one of the elongated spinal rods such that a spinal rod extends vertically along at least a portion of the length of the spine on each side of the spinal midline.
U.S. Pat. No. 5,683,392 to Richelsoph et al. (xe2x80x9cthe ""392 patentxe2x80x9d) discloses a multi planar locking mechanism for securing a spinal rod to the spinal column. The ""392 patent is incorporated herein by reference in its entirety.
Connector systems for transversely and rigidly connecting adjacent spinal rods together are also well known. Such connector systems are beneficial because they restrict spinal rod migration and increase the overall stiffness of the spinal rod system. In procedures involving multi-level fusion of the spine, a transverse connector system may be essential during the post operative period to minimize the amount of motion permitted between the spinal rods. By providing a rigid transverse connection between adjacent spinal rods, a stiffer construct can be created to enhance the promotion of spinal fusion.
U.S. Pat. No. 5,947,966 discloses a transverse connector system for linking adjacent spinal rods together. In one embodiment, the system includes first and second connector portions which are slidably adjustable in relation to each other. Each connector portion includes an engaging member configured to receive a spinal rod. A wedge member is provided in each engaging member to secure each connector portion to the spinal rod. The wedge member includes a screw for engaging and biasing the spinal rod into a receptacle defined by the engaging member. Because of the orientation of the wedge members with respect to the engaging member, it is sometimes difficult to position and secure a spinal rod within the receptacle of an engaging member.
Accordingly, a need exists for an improved spinal rod connector system which can be easily and quickly secured between adjacent spinal rods to provide a rigid stabilizing system.
In accordance with the present disclosure, a rod-to-rod coupler is provided which includes a body having first and second coupler portion. Each coupler portion defines a concavity configured to receive a portion of an elongated spinal rod. A screw and nut assembly is positioned adjacent each concavity. Each screw and nut assembly includes a screw and a flanged nut. Each flanged nut has a flange portion which extends at least partially over a concavity. After the rod-to-rod coupler has been positioned with the concavities located over adjacent spinal rods, the screw can be rotated to move the flange nut into engagement with a spinal rod to secure the spinal rod within a concavity.
In an alternate embodiment, one coupler portion includes a blind bore and the other coupler portion includes an extension which is slidably received within the blind bore. The extension is slidable within the blind bore to selectively adjust the distance between the concavities of the first and second coupler portions. A set screw is provided to secure the extension at a fixed position within the blind bore.